The present invention generally relates to optical interconnects, and more particularly to an optical interconnect between processor nodes.
Optical interconnects for various processor arrangements have become popular in part because of high bandwidth and lost cost. However, the particular arrangement by which the processors are interconnected with optical fiber may create a single point of failure as well as create bandwidth allocation challenges.
For example, an optical interconnect is used in some applications to connect a plurality of processors for interprocessor communication. The optical fibers are coupled to the processors and interconnected at a centralized switch. The centralized switch receives from the processors information packets in the form of optical signals. The switch converts the optical signals to electrical signals, decodes the packet header to determine the destination processors, converts the electrical signals back to optical signals, and routes the optical signals to the proper destination processors. Because all the optical fibers are routed to the single central switch, this interconnect is prone to a single point of failure. Furthermore, if the central switch receives at the same time multiple packets that are addressed to the same processor, a prioritization scheme must be exercised to route the packets. The single point of failure and bandwidth limitations must be considered in implementing this interconnect in a particular application.
An interconnect system and a method that addresses the aforementioned problems, as well as other related problems, are therefore desirable.
An optical-interconnect node, arrangement, and method are disclosed in various embodiments of the invention. In one embodiment, an optical-interconnect node includes a an optical-link section and a processor-link section. The optical-link section includes an optical combiner and an optical splitter. The combiner combines an optical signal of a local node with optical signals from other connected nodes, and the combined signals are carried on a common waveguide. Each node has an optical splitter that splits the optical signals for local processing. The processor-link section includes a demultiplexer and a transmitter. The optical signals from a splitter are input to a demultiplexer, which separates and converts the optical signals to respective electrical signals. The transmitter converts a local electrical signal to an optical signal having a wavelength associated with the node.
In a system embodiment, a plurality of nodes are coupled via the optical combiners and optical splitters.
It will be appreciated that various other embodiments are set forth in the Detailed Description and Claims which follow.